This post was originally created by Nat Iwata for another site but never got posted. Today we’re sharing some “master’s secrets.” The examples shown are all from Wind Up Robots.
1: Use a good UV grid texture
A good UV texture can easily be found online. Using a texture with multiple colors and numbers, as opposed to a simple checker pattern, will help make it easier to keep track of where each UV shell is located on the UV space as it relates to the model.
2: Keep scale consistent
All of the individual UV shells should be scaled so that they show the same sized pixel density on the model. When using a UV grid texture, this will mean that the grid is the same size across the model.
The exception to this rule would come when certain parts of a model were never going to be close to the camera, in which case these UV’s could be scaled accordingly.
3: Minimize seams and stretching
It’s often a balancing act trying to minimize both the seams and stretching/distortion when laying out UV’s. Seams can be hidden by placing them at less visible parts of the model (e. g. under the arm of the character), or by placing them on hard edges.
While distortion can often be solved by splitting the shell up with more seams, this can make it very difficult for the texture artist to paint.
Something to always keep in mind is “What is the texture going to be?” Are there linear lines or patterns, or is it a more organic shape? A texture with straight lines, or geometric shapes will be much more obviously affected by distortion, as opposed to a more organic looking texture. Especially in low poly modeling, different methods of stacking and folding UV’s can help with seams. Choose wisely and be creative.
4: Consistent Orientation
Although it can sometimes interfere with laying out your UV’s with the least amount of wasted space, orienting UV shells in a consistent manner will make it easier for the texture artist to visualize how things are going to look on the model.
Especially when painting any lighting or highlights, orienting UV’s so that up is positive Y on the model is a good idea. Again, this practice needs to be balanced with good tight UV layout. Making things a little easier on the texture artist is not worth losing a lot of pixel resolution because of wasted space on the sheet.
Less wasted space on your UV sheet directly translates into greater pixel density for the texture on your model. Not to completely conflict with the previous practices, things can be rotated or seams added if it means being able to utilize more space. Again, you may have a lot more creative freedom with this if you are working on low poly game models. Multiple parts with the same texture, or even very similar texture, can often be stacked and share the same UV space. Sometimes splitting a mesh down the center so that it’s texture can be mirrored is worth more in gained UV space than it is to have unique textures on each side.